Hello Michael:
The 180 or 280 appeal to me since the sensor plus output is 20mp. I often find myself in situations were I can't get a fast enough shutter speed to stop motion, This is especially true in the early morning or late evening times. Sensor plus output is excellent up to 800 and still quite good a 1600. The downside of this on the 260 is only having 15mp images. I feel I can get to a larger print from the 20mp sensor plus but the 15mp would be a stretch. There are also times I would like to have iso 35.
The IQ260 is pretty much iso 50 to 200 (200 is great in good light, not so good in low light). Past 200 and you really start to see quite a bit of image degradation especially shadow areas, as these become pretty worthless. Shadows will lack all detail and show a lot of smearing. You will also start to see a good bit of overall loss of saturation and image sharpness seems to suffer also. I had hoped that the IQ260 would have more range due to the new sensor design and ability to shoot at iso 140 or 200 in the long exposure mode, but so far, I can't really tell much difference between 100 and 200 in normal mode and 140 and 200 in long exposure mode. I have not used the IQ260 for any "long exposures" yet so I don't know what to expect from that. I have also realized now that even at iso 50, the shutter speed used can make a huge difference in the results the sensor can achieve, at times the difference of even 1/2 a second can make a big difference in final output range in the shadows. One HUGE limitation of the tech camera solution is the lack of 1/3 shutter increments. The Copal shutter's 1 stop incremental range causes this. Hopefully tech camera companies are working towards new solutions, besides the current and future electron shutters as they as both too expensive and require a PC to fire.
I have also realized that the IQ260 has more top end range than I at first realized, in that you can easily pull back a shot that appears to be as much as 1 full stop overexposed (speaking to highlights here). This is a plus for me since much of my landscape work will have elements that will easily get blown out, clouds or water tend to be the most common. Shooting tethered in the field is a great asset as you can quickly work up a shot in C1 and determine if you have totally blown the highlights or not. I realize the histogram is available, but often times, in select areas of a shot the histogram won't tell me as much as I need to know. My point here: the CCD likes light, and works well with it, however even at base iso, under exposure with a CCD can cause excessive noise. With the modern CMOS chips, like the Sony chip in the D800, this is not true, as you can easily expose a shot with as much as 1.5 of underexposure and pull up the shot with basically no noise.
The Dalsa CCD technology in the IQ260 does make for an excellent shot and I do love the color from the images. On a bright day, the 260 can produce some really wonderful shots. On a dull day, the IQ260 can also do a good job if the scene will allow for shutter speeds approaching 1/15th to 1/4 of a second at iso 50. The added details I can pull by using a tech camera and wides is very impressive.
Early on I was very interested in "upgrading" to a IQ250, however the price from Phase One for the "upgrade" was financially impossible to work with. My 260 is still less than 1 year old.
As a tech camera user 100% of the time, I was hoping to see more tests showing how well the IQ250 will work with tech lenses. There was a lot of buzz at first, and the initial testing showed that were some possible issues mainly on extreme shifts. However the testing I saw was all indoors, and I would still like to see so traditional landscape shots, with some 15mm or so shifts. The main limiting issue to me on the IQ250 however is the 1.3 crop on the sensor. I was on a shoot this past Monday and the full frame sensor just barely got the shot I wanted. I had limited movement allowed to me for this shot. I have seen great images taken from the Alpa FPS and Canon TS-E lenses, but I am not going to switch from Arca and the rm3di. Again way to much cost involved.
I think over time, if I moved to a 250, I would just work into the 1.3 crop and it's limitations would just become part of my workflow. No doubt I would love to have iso 400 in full resolution and the ability to have good details in my shadows. I am hoping maybe later in the year to rent a 250 and shoot it side by side against my 260. This is only way to really tell if I like the results. It would be more of fact finding shoot as the cost to upgrade/downgrade (not sure what it would be since I loose 10MP and 30"% of my sensor) from Phase One makes this consideration a non issue for me currently.
I am sure Phase has a plan to get to full frame CMOS by 2015, but I am also wondering if the chip will be a Sony? Dalsa has yet to produce a CMOS chip that I am aware of for either 35mm or MF, so for them it would be a first round, Sony has had years of work and experience and their efforts have paid off.
Paul
